1. Technical Field
The present invention is related to a circuit protection structure, and particularly to a circuit protection structure used for wireless communications.
2. Related Art
For the currently available wireless communications circuit structures, a stripline, coupled stripline, microstrip, coupled microstrip, coplanar waveguide (CPW) and CPW ground structures are comprised.
Referring to FIG. 1A, which is a 3 dimensional view of a related art stripline structure.
The stripline structure has a base circuit board 10, which comprises a first face 11 and a second face 12 opposed to the first face 11. In the base circuit board 10, wireless communications signal lines 20. The first and second faces 11, 12 are an overall face form of grounding line 30. Thus, the characteristic resistance of the wireless communications signal lines 20 is apt to be controlled and has a relatively better shading characteristic. However, wireless communications involve a slow transmission speed.
Referring to FIG. 1B, in which a 3 dimensional view of a related art coupled stripline structure is illustrated.
The coupled stripline structure has a base circuit board 10 which comprises a first face 11 and a second face 12 opposed to the first face 11. In the base circuit board 10, wireless communications signal lines 20. The first and second faces 11, 12 are an overall face form of grounding line 30. The coupled stripline structure has its characteristic in that the characteristic resistance of the wireless communications signal line 20 may be controlled simply by controlling a thickness and a width of the two wireless communications signal lines 20, a dielectric constant of the base circuit board 10 and a distance between two layers of grounding line 20. Further, since the first face 11 and the second face 12 has the overall face form of grounding line 30, the characteristic resistance of the wireless communications signal line 20 is apt to be controlled and has a relatively better shading characteristic. However, the wireless communications involve a slower transmission speed. But, the coupled stripline structure has a larger bandwidth as compared to that of the stripline structure.
Referring to FIG. 1C, which is a 3 dimensional view of a related art microstrip structure.
The microstrip structure has a base circuit board 10, which comprises a first face 11 and a second face 12 opposed to the first face 11. In the base circuit board 10, wireless communications signal lines 20. The first and second faces 11, 12 are an overall face form of grounding line 30. The microstrip structure has its characteristic in that the characteristic resistance of the wireless communications signal line 20 may be controlled simply by controlling a thickness and a width of the wireless communications signal line 20, and a distance between the wireless communications grounding line 20 and the grounding line 30. Further, since the wireless communications signal line 20 has one of the first and second faces 11, 12 contacting with the base circuit board 10 and the other contacting with air, a larger transmission speed of wireless communications signal may be possessed, but involves a poorer shading characteristic owing to the ambient radiation interference.
Referring to FIG. 1D, in which a 3 dimensional view of a related art coupled microstrip structure is illustrated.
The coupled microstrip structure has a base circuit board 10 which comprises a first face 11 and a second face 12 opposed to the first face 11. In the base circuit board 10, wireless communications signal lines 20. The first and second faces 11, 12 are an overall face form of grounding line 30. The coupled microstrip structure has its characteristic in that the characteristic resistance of the wireless communications signal line 20 may be controlled simply by controlling a thickness and a width of the two wireless communications signal lines 20, and a distance between the two layers of grounding line 20. Further, since the wireless communications signal line 20 has one of the first and second faces 11, 12 contacting with the base circuit board 10 and the other contacting with air, a larger transmission speed of wireless communications signal may be possessed, but involves a poorer shading characteristic owing to the ambient radiation interference. However, the coupled microstrip structure has a larger bandwidth as compared to that of the stripline structure.
Referring to FIG. 1E, which is a 3 dimensional view of a related art CPW structure.
The CPW structure has a base circuit board 10, which comprises a first face 11 and a second face 12 opposed to the first face 11. In the base circuit board 10, wireless communications signal lines 20. The first and second faces 11, 12 are an overall face form of grounding line 30. The CPW structure has its characteristic in that the characteristic resistance of the wireless communications signal line 20 may be controlled simply by controlling a thickness and a width of the wireless communications signal line 20 and a distance between the wireless communications grounding line 20 and the grounding line 30. Further, since the wireless communications signal line 20 and the grounding line 30 are both disposed on the first face 11 of the base circuit board 10 in the CPW structure, the required manufacturing steps are reduced and the in-series and in-parallel forming for the wireless communications signal line 20 and the grounding line 30 and the electronic components is easy, without requiring additional through-holes on the microstrip structure, which may bring an uneglectible inductance effect and thus reduce an efficiency of high frequency wireless communications.
Referring to FIG. 1F, which is a 3 dimensional view of a related art CPW ground structure.
A wireless communications signal lines 20 is disposed on the face 11 of the base circuit board 10. A grounding line 30 is disposed on the first face 11 of the base circuit board 10 and two sides of the wireless communications signal line 20. The CPW ground structure has its characteristic in that the characteristic resistance of the wireless communications signal line 20 may be controlled simply by controlling a thickness and a width of the wireless communications signal lines 20 and a distance between the wireless communications grounding line 20 and the grounding line 30.
However, the above wireless communications circuit structure has a common characteristic of a completeness of the wireless communications signal line and grounding line. Through the completeness, a loss in the wireless communications frequency range of 800 MHz to 6 GHz is approximately 0 dB and a good wireless communications result is achieved. However, since the completeness may cause the internal system ground and external ground to be not separable, i.e. the wireless communications circuit structure cannot provide electromagnetic susceptibility (EMS), electrostatic discharge (ESD) and electricity leakage proofing ability. Correspondingly, the internal system may be interfered with EMS and affected by ESD, which may further lead to a system failure and scratch.
To provide the EMS, ESD and electricity leakage proofing ability, the wireless communications signal line and the grounding line have to be separated to each other in the wireless communications circuit structure, causing the loss in the frequency range of 800 MH to 6 GHz to be larger than 30 dB, i.e. the wireless communications result cannot be provided.
In view of the above, it is known that the currently available wireless communications circuit structure has long encountered the problems of EMS, ESD, electricity leakage proofing ability and exclusive characteristic of wireless communications functions. Therefore, it is quite a need to set forth an improved technique to settle down the associated issue.